diff --git a/src/draw.c b/src/draw.c
index 95a4527..efc8fce 100644
--- a/src/draw.c
+++ b/src/draw.c
@@ -359,7 +359,9 @@ akerr_ErrorContext AKERR_NOIGNORE *akgl_draw_flood_fill(akgl_RenderBackend *self
     SDL_Surface *target = NULL;
     SDL_Surface *rgba = NULL;
     SDL_Texture *patch = NULL;
-    SDL_Rect dirty;
+    // Only written by a successful flood_region(), and only read after one, but
+    // the paths in between are far enough apart that the compiler cannot see it.
+    SDL_Rect dirty = { 0, 0, 0, 0 };
     SDL_FRect src;
     SDL_FRect dest;
     uint32_t *pixels = NULL;